1. Field of the Invention
The present invention relates to a light-emitting device including a light-emitting element such as an electroluminescence (EL) element.
2. Description of the Related Art
EL display devices are known as active matrix display devices. A screen of an active matrix EL display device includes a plurality of pixel circuits. Each pixel circuit is provided with an EL element. In the EL display device, the pixel circuit controls the luminance of the EL element so that gray scale display is performed.
In the general structure of an EL element provided in a pixel circuit, a light-emitting layer is provided between a pair of electrodes of an electrode having a light-transmitting property and an electrode having a light-reflecting property. Light generated from the light-emitting layer is reflected by the electrode having a light-reflecting property, passes through the electrode having a light-transmitting property, and is extracted. In general, an electrode having a light-transmitting property (hereinafter it may be referred to as a light-transmitting electrode) and an electrode having a light-reflecting property (hereinafter it may be referred to as a reflective electrode) functions as a cathode and an anode, respectively, in an EL element.
In a screen of an EL display device, a number of reflective electrodes are regularly arranged. Thus, there is a problem in that these reflective electrodes function like mirrors and reflect an image in the screen. Further, the regular arrangement of the reflective electrodes might cause diffraction of light reflected by each reflective electrode, so that interference fringes might appear on the screen. One method for solving such a problem is to make the surface of the reflective electrode uneven. In Patent Documents 1 and 2, to form projections and depressions on and in the surface of a reflective electrode, a light-transmitting electrode (cathode), a light-emitting layer, and a metal electrode (anode) are stacked in this order over a resin film having dot-like projections and depressions.